This system features the 4-piston, S4 caliper mounted to a 13", 1 piece slot, drill, zinc plated rotor. The S4 caliper has D.O.T compliant dust and weather seals and uses the popular DR1 pad type. Billet aluminum hubs come assembled with premium bearings packed with Redline synthetic grease and billet dust caps. All mounting brackets, stainless braided hoses and hardware are also included. The 13" SS4 is designed to fit most 17" or larger wheels.